ARDMORE, Pa. — The horn that suspended play at the U.S. Open also turned out to be the official signal to shop.

Forget Ian Poulter. The real early leader at Merion Golf Club was the merchandise tent — all three of them. Those crackles of thunder led to plenty of ka-chinging at the stores.

Storms were expected in the Philadelphia area for most of Thursday, and when the alert sounded at 8:36 a.m., thousands of fans left their perches in the grandstands and went in search of souvenirs — $45 umbrellas and $27 hats.

“We were so excited but we really didn’t even get to see anything,” said Samantha Jaffee, holding $88 worth of Open items.

So she followed the lead of hundreds of others, browsing through racks of $95 shirts along with posters, books and bags.

Aside from the big, white souvenir tents, there were few options to escape the storm, so fans took advantage of any covered area, no matter the size — a small ATM machine booth, a USGA survey tent that was mostly empty during practice rounds.

All the while, there were announcements on screens and from public safety officials telling spectators to seek shelter; weather warning signs flashed on leader boards around the course.

“Safety is paramount so flexibility is employed,” USGA spokesman Dan Hubbard said. “This means (the) clubhouse or other restricted areas may be made available, if needed.”

USGA officials said about 17,000 fans were on the course when the horn sounded. Weather alerts were posted on video boards around the course and fans were directed to the tents, buildings, busses, even nearby Haverford College for shelter, director for Open championships Mike Butz said.

Fans also were kept updated on weather and safety procedures through social media and other websites.

“I think the plan we put in place, in a lot of ways, was a good trial run for us,” Butz said.

“The plan itself worked really well.”

The USGA quickly suspended transportation from three main lots to Merion, though service continued for anyone who wanted to call it a day and leave. Which brings us to refunds.

If there is less than a full four hours of play, U.S. Open championship director Reg Jones said there could be refunds or tickets “possibly” could be used another day. The tournament was less than two hours old when the horn blew but resumed shortly after noon under mostly sunny skies.

To be sure not everyone went shopping in the rain. It made people want to eat, too.

There’s nothing worse than being wet and hungry but a cheesesteak, $9.50, please, just might be able to make it more bearable.

Some washed-out spectators complained that breakfast sandwiches were already sold out by 9 a.m.

“This is the worst,” Tim McDermott, of Philadelphia, said as he ate a Thai chicken wrap. “Who runs out of bacon, egg and cheese at breakfast? It’d be fine if I could drink a beer, but you can’t do that before 10:30.”

Ralph Pelusi, of Hatboro, arrived at the 14th green around 8:15 a.m, just before the horn sounded.

“It’s tough, but we’ll wait it out,” Pelusi said. “It’s a bummer.”

Bill Strehse, who lives about four blocks away, was part of the scramble for shelter.

“Everybody ducked under what they could find. Every tent was filled. And this place was a wall,” he said, pointing to the large covering at the entrance. “I had my poncho and just waited under the tree and watched the lightning. Once the rain started, everyone found a spot to hang out.”

Some, like 16-year-old Geoff Warke of Hershey, simply popped open an umbrella and walked the front nine. He even got a quick hello from Phil Mickelson near the fourth fairway.

By mid-afternoon, the black-and-white umbrellas imprinted with “Merion 2013” were used to shield folks from the sun.

Brian Furio, of York, bought one during the downpour and used it more as a walking stick in the afternoon.

“If I stay long enough, I’ll be ready,” he said.

At a fan zone, where a replay of the limited morning action was up on the big screen, a worker took the microphone to implore an overflow crowd to move to the merchandise tent.

“We’re not feeling safe having this many people in here,” he told them.